package com.hit.basmath.interview.top_interview_questions.medium_collection.math;

import java.util.HashMap;
import java.util.Map;

/**
 * 166. Fraction to Recurring Decimal
 * <p>
 * Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.
 * <p>
 * If the fractional part is repeating, enclose the repeating part in parentheses.
 * <p>
 * Example 1:
 * <p>
 * Input: numerator = 1, denominator = 2
 * Output: "0.5"
 * <p>
 * Example 2:
 * <p>
 * Input: numerator = 2, denominator = 1
 * Output: "2"
 * <p>
 * Example 3:
 * <p>
 * Input: numerator = 2, denominator = 3
 * Output: "0.(6)"
 */
public class _166 {
    public String fractionToDecimal(int numerator, int denominator) {
        if (numerator == 0) {
            return "0";
        }
        StringBuilder fraction = new StringBuilder();
        // If either one is negative (not both)
        if (numerator < 0 ^ denominator < 0) {
            fraction.append("-");
        }
        // Convert to Long or else abs(-2147483648) overflows
        long dividend = Math.abs(Long.valueOf(numerator));
        long divisor = Math.abs(Long.valueOf(denominator));
        fraction.append(String.valueOf(dividend / divisor));
        long remainder = dividend % divisor;
        if (remainder == 0) {
            return fraction.toString();
        }
        fraction.append(".");
        Map<Long, Integer> map = new HashMap<>();
        while (remainder != 0) {
            if (map.containsKey(remainder)) {
                fraction.insert(map.get(remainder), "(");
                fraction.append(")");
                break;
            }
            map.put(remainder, fraction.length());
            remainder *= 10;
            fraction.append(String.valueOf(remainder / divisor));
            remainder %= divisor;
        }
        return fraction.toString();
    }
}
